That's good if you remember the first time. I'm sure she did too! 😉
But putting it all back on track..yep that audio needs phase alignment no different from the carriers needing phase alignment as well.
Not all that easy considering how those signals are to get from point A to point B over a 1/4 mile distance.
Delay!!! Nothing but delay!!
Again referencing what was done in the analog video world, delay lines or modules were used to delay the pulses so that everything in the racks seen those pulses at the exact same time domain. Equipment close to those delay lines would be adjusted with more delay than those further away from the router or switcher.
Same must be done with the audio and reference pulse for a multiple transmitter system working in the analog world.
RFB
If something is to be ongoing there is no way of avoiding a first time.
As I figure it, if an audio delay between two transmitters on the same frequency were exactly right, the listeners in the middle would get a grand echo chamber like being in the Taj Mahal, known for its long delay echo.
If the delay were "rolled" or "shifted in time" it could provide a flanging effect that might be fun to hear.
I wonder if there is a time-stretching/shrinking tool on Audacity, the audio editing program. I'll go check.
"I wonder if there is a time-stretching/shrinking tool"
This is why I also mentioned something would be needed to measure both the audio and carrier phasing, and do "on the fly" adjustments to each site to keep things in order. Static adjustments left to drift due to temperature or propagation or component aging won't work at all.
Again referencing the analog video world, checking the system's "timing" was a regular maintenance routine done at least once a week.
But that was with gear located in a controlled environment too.
RFB
In producing video from different cameras or several sources I would adjust the vector/waveform monitors for each bit of video. Constant tweaking job, but the results were worth the effort.
With stereo reel-to-reel tape, the timing weakness was head alignment between record and playback heads and between different machines. Despite the fact that there were standard test tapes for setup, tape was just too flexible to remain exactly on coarse and azimuths needed to be watched on an oscilloscope, another example of a timing problem.
The fragile nature of timings in multiple-same-frequency-transmitters reminds me a lot of tape head azimuth, in that it is, as RFB points out, very close to the edge.
The central timing approach of the Rangemaster is probably the most stable way to manage the RF part of the problem.
"The central timing approach of the Rangemaster is probably the most stable way to manage the RF part of the problem."
Problem still exists with phase delays caused by reference and audio signals traveling along a line or via RF signal, which introduces the propagation delay factors. Thus a measuring and adjustment system must be put in there at each TX point.
Perhaps much of it can be resolved using GPS reference...until the Sun outages come into play, which at that point the system would have to rely on a local reference..again taking into consideration the correcting of the correction pulse's phase to each TX.
Starting to get as complex as phase alignment of a frigging warp core!
RFB
This all reminds me of one of those great Einstein quotes that we hear every once in awhile...
"Nothing in the universe is simultaneous."
Einstein also said..
"Nothing in the universe is static".
RFB
All static is found on the AM radio band.
All static today is caused by iBelch.
RFB